Welcome to Quantum Magazine's podcast.

Each episode, we bring you stories about developments in science and mathematics.

I'm Susan Vallett.

A behavioral neuroscientist in Switzerland suspected that a deficit in cellular energy might explain the lack of motivation

that anxiety-prone people experience. Do mitochondria play a role in our mental health?

Carmen Sandy recalls the skepticism she faced at first.

Sandy is a behavioral neuroscientist at the Swiss Federal Institute of Technology in Lausanne.

She had followed a hunch that something going on inside critical neural circuits could explain anxious behavior.

She suspected something beyond brain cells and the

synaptic connections between them. The experiments she began in 2013 showed that neurons

involved in anxiety-related behaviors showed abnormalities. Their mitochondria, the organelles often

described as cellular power plants, didn't work well.

They produced curiously low levels of energy. Those results suggested that mitochondria might be involved in

stress-related symptoms in the animals. But that idea ran contrary to the synaptocentric vision of the brain

held by many neuroscientists at the time. Her colleagues found it hard to believe Sandy's evidence

that in anxious individuals, at least in rats, mitochondria inside key neurons might be important.

Here's Sandy talking with reporter Elizabeth Landau.

Yeah, they were very skeptical. Then whenever I presented the data, they told me it's very interesting,

but you got it wrong. The mitochondria is not going to be different. It's just going to be very dynamic, which is true, we know, but only as if it could be modified by the activity of the circuit and nothing else. And this is not true.

A growing number of scientists have joined her during the past decade or so. They wonder whether mitochondria might be fundamental,

not just to our general physical well-being, but specifically to our mental health. In particular,

they've explored whether mitochondria affect how we respond to stress and conditions like

...